ABSTRACT

Metal catalysts are of particular interest for reactions involving hydrogen, such as hydrogenation, hydrogenolysis, and catalytic reforming. The uses of iron for ammonia synthesis and for the Fischer Tropsch reaction and nickel for steam reforming and methanation are important examples of catalysts. New metal zeolite catalysts were developed for cracking of heavy feed with high sulfur and high nitrogen content, yielding various products. Maximum catalytic activity is associated with rapid but not too strong chemisorption of reactants. Hydrogenolysis of a hydrocarbon is the cleavage of the C-C bond accompanied by hydrogenation to form two molecules from one. Hydrogenolysis of paraffins is of great importance in petroleum processing (there termed as “hydrocracking”) in which it is sometimes a desired reaction as in commercial hydrocracking and sometimes not desired, as in catalytic reforming. Metal-containing zeolites can be used as catalysts for different purposes and under various conditions. Therefore, their composition, preparation, and activation depend on the process used.